Several cynical Slashdot readers question Microsoft's motives for doing so, but as SpotBug pointed out, fights don't have to be Good vs. Evil, "Fights can be Evil vs. Evil, too." And on that subject, I must copy Noryungi's hilarious post here:

DEATH STAR (AP) 2003/06/18 --

Darth Vader, Lord of Sith and Supreme Commander of the Imperial Fleet, has announced today his intention to sue Sauron of Mordor, the official "Dark Lord" of Middle Earth, for violating his Intellectual Property (IP).

Darth Vader spokesdroid K4VC5 briefly commented to the intergalactic press: "Darth Vader is, most certainly, the original Dark Lord, and we feel that Sauron of Mordor, no matter how creative and evil, has no right to call himself the 'Dark Lord' of Middle Earth". He added that Darth Vader legal team would pursue damages worth "several billions" of Galactic Credits.

Sauron, Dark Lord of Middle Earth, was unavailable to comment, but well-informed sources close to Mordor report that "his evilness" promised to rain death and destruction on the first legal storm trooper to ever set foot on Middle Earth.

Darth Vader spokesdroid also confirmed that Lucifer, the star attorney of Mephistopheles, Baal, Satan & Associates Law Firm (LLC) has been retained to defend a case which promises to be one of the toughest legal fight in the history of Evil(tm).

Lucifer first (and best known) legal battle involved the semitic God YHWH (pronounced: "Yahweh") for the control of the "Garden of Eden" real-estate property. That case was widely considered a draw, and was settled out of court.

Dr Evil, widely considered as an authority on Evil(tm) only commented: "Bwa ha ha ha ha ha!", and declined to elaborate any further.